wrote
Harry Bloomfield wrote

My new concern is that we sometimes get automated calls
from the electric, gas, flood and water utilities, when they
have an issue and we obviously want these calls to get through

If you've no electricity because of a power cut or a flood,
most call filtering devices (and cordless phones) won't
work anyway, and won't pass the call through to you.

But it will work fine when the utlity is warning you about an impending
flood or the power being off for hours when maintenance is being done.